Can You Freeze-Dry Strawberries Without A Machine?

June 20, 2024 by Kristina Panos 45 Comments

Summer has settled upon the northern hemisphere, which means that it’s time for sweet, sweet strawberries to be cheap and plentiful. But would you believe they taste even better in freeze-dried format? I wouldn’t have ever known until I happened to get on a health kick and was looking for new things to eat. I’m not sure I could have picked a more expensive snack, but that’s why we’re here — I wanted to start freeze-drying my own strawberries.

While I could have just dropped a couple grand and bought some kind of freeze-drying contraption, I just don’t have that kind of money. And besides, no good Hackaday article would have come out of that. So I started looking for alternative ways of getting the job done.

Dry Ice Is Nice

Dry ice, sublimating away in a metal measuring cup. — Image via Air Products

Early on in my web crawling on the topic, I came across this Valley Food Storage blog entry that seems to have just about all the information I could possibly want about the various methods of freeze-drying food. The one that caught my eye was the dry ice method, mostly because it’s only supposed to take 24 hours.

Here’s what you do, in a nutshell: wash, hull, and slice the strawberries, then put them in a resealable bag. Leave the bag open so the moisture can evaporate. Put these bags in the bottom of a large Styrofoam cooler, and lay the dry ice on top. Loosely affix the lid and wait 24 hours for the magic to happen.

I still had some questions. Does all the moisture simply evaporate? Or will there be a puddle at the bottom of the cooler that could threaten my tangy, crispy strawberries? One important question: should I break up the dry ice? My local grocer sells it in five-pound blocks, according to their site. The freeze-drying blog suggests doing a pound-for-pound match-up of fruit and dry ice, so I guess I’m freeze-drying five entire pounds of strawberries. Hopefully, this works out and I have tasty treats for a couple of weeks or months. Continue reading “Can You Freeze-Dry Strawberries Without A Machine?” →

Probably The Cheapest Mac Emulation Hardware

June 20, 2024 by Jenny List 20 Comments

There are many ways to build your own Macintosh clone, and while the very latest models remain a little inaccessible, there are plenty of Intel-based so-called “Hackintoshes” which deliver an almost up-to-date experience. But the Mac has been around for a very long time now, and its earliest incarnation only has 128k of RAM and a 68000 processor. What can emulate one of those? Along comes [Matt Evans], with a working Mac 128k emulated on a Raspberry Pi Pico. Such is the power of a modern microcontroller that an RP2040 can now be a Mac!

The granddaddy of all Macs might have been a computer to lust after four decades ago, but the reality was that even at the time the demands of a GUI quickly made it under-powered. The RP2040 has plenty of processing power compared to the 68000 and over twice the Mac’s memory, so it seemed as though emulating the one with the other might be possible. This proved to be the case, using the Musashi 68000 interpreter and a self-built emulator which has been spun into a project of its own called umac. With monochrome VGA and USB for keyboard and mouse, there’s MacPaint on a small LCD screen looking a lot like the real thing.

If you want a 1980s Mac for anything without the joy of reviving original hardware, this represents an extremely cheap way to achieve it. If it can be compiled for microcontrollers with more available memory we could see it would even make for a more useful Mac, though your Mac mileage may vary.

Of course, this isn’t the only take on an early Mac we’ve brought you.

UV-K5 All-Band Mod, Part 2: Easier Install, Better Audio, And Two Antennas

June 20, 2024 by Dan Maloney 46 Comments

OK, it’s official: the Quansheng UV-K5 is the king of hackable ham radios — especially now that a second version of the all-band hardware and firmware mod has been released, not to mention a new version of the radio.

If you need to get up to speed, check out our previous coverage of the all-band hack for the UV-K5, in which [Paul (OM0ET)] installs a tiny PCB to upgrade the radio’s receiver chip to an Si4732. Along with a few jumpers and some component replacements on the main board, these hardware mods made it possible for the transceiver, normally restricted to the VHF and UHF amateur radio bands, to receive everything down to the 20-meter band, in both AM and single-sideband modulations.

The new mod featured in the video below does all that and more, all while making the installation process slightly easier. The new PCB is on a flexible substrate and is considerably slimmer, and also sports an audio amplifier chip, to make up for the low audio output on SSB signals of the first version. Installation, which occupies the first third of the video below, is as simple as removing one SMD chip from the radio’s main board and tacking the PCB down in its footprint, followed by making a couple of connections with very fine enameled wire.

You could load the new firmware and call it a day at that point, but [Paul] decided to take things a step further and install a separate jack for a dedicated HF antenna. This means sacrificing the white LED on the top panel, which isn’t much of a sacrifice for most hams, to make room for the jack. Most of us would put a small SMA jack in, but [Paul] went for a BNC, which required some deft Dremel and knife work to fit in. He also used plain hookup wire to connect the jack, which sounds like a terrible idea; we’d probably use RG-316, but his mod didn’t sound that bad at all.

Keen to know more about the Quansheng UV-K5? Dive into the reverse-engineered schematics.

Continue reading “UV-K5 All-Band Mod, Part 2: Easier Install, Better Audio, And Two Antennas” →